<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>弹性盒子-flex</title>
  <style>
    .wrapper {
      display: flex;
    }
    .wrapper > div {
      width: 200px;
      height: 100px;
      background-color: #a5a5a5;
      text-align: center; /*水平居中*/
      line-height: 100px; /*垂直方向居中*/
      /*去除尾部空白*/
      flex: 1;
    }
  </style>
</head>
<body>
<div class="wrapper">
  <div class="box1">One</div>
  <div class="box2">Two</div>
  <div class="box3">Three</div>
</div>
</body>
</html>